Motions of Stars in a Star Cluster, M92

Abstract

Observational tests of theories of stellar evolution are typically based on star clusters, where many stars of essentially equal ages and at approximately the same distance from the earth can be studied and compared. In such studies, however, one must remove the contamination of foreground and background stars which are unrelated to the cluster. This is done well via stellar motions, since cluster members should move together whereas the non-members should show a wide variety of motions. The stars of the globular cluster, M92, are among the oldest stars in our Galaxy. The globular cluster M92, also referred to as NGC 6341, located at 17 h 15 m 6 + 43 12’ (1950) is one of the most metal-poor objects in our galaxy. As such it has been the subject of numerous investigations.